The present invention relates to a system (method and apparatus) for retrieving secure information from a mass storage medium such as a CD-ROM, for temporary storage and usage by an information user.
Systems for storage and retrieval of secure information are well known in the art. As used herein, the term "secure information" is intended to mean information (alphanumeric data, graphics and the like) which is either encrypted or otherwise protected to prevent access thereto except by an authorized user. Such systems have been proposed and are employed both for the case where the information source (database) is centralized, and for the case where the information source has been distributed to multiple users. In the latter case, CD-ROMs have been used to export databases to multiple users so that information storage and retrieval takes place at the user site.
In the U.S. Pat. No. 5,010,571 to Ron Katznelson and the U.S. Pat. Nos. 4,827,508, 4,977,594 and 5,050,213 to Victor Shear, it is proposed to provide encrypted digital information on CD-ROMs at the user site and to monitor and account for each item or "packet" of information which is retrieved and decrypted from a CD-ROM by an authorized user.
This concept of retrieving information on a "pay-as-you-go" basis is also disclosed in the U.S. Pat. No. 5,247,575 of Peter J. Sprague and Thomas H. Lipscomb to include individual access to encrypted data which is "broadcast" to multiple user sites from a central source and/or to provide individual access to encrypted data stored at a central source, using conventional time sharing techniques and transmission via telephone dial-up or local area network (LAN) or wide area network (WAN) communication.
All of these prior art systems permit the user's access to the secure information to be monitored and strictly controlled. This is accomplished, in practice, by maintaining a record at each user site of each information packet which is retrieved and the cost thereof to the user, and then "polling" all user sites from a remote central site, on a regular basis, to retrieve the user data and, if necessary, disable the equipment at one or more user sites to prevent further access to the secure information at these sites.
Systems of this type require specialized electronic circuitry at each user site which operates in cooperation with a central computer at a remote site. Particularly when decryption must be effected at each user site, it is difficult to maintain the security and integrity of this electronic equipment.
Furthermore, the provision of an electronic circuit board, or the like, to a personal computer at a user workstation can (actually or apparently) compromise the integrity of this computer, thus making the system difficult to implement in practice.